CVE-2026-1225

Malicious logback.xml configuration file allows instantiation of arbitrary classes

State
Published
Severity
1.8 Low
Published
Jan 22, 2026
Updated
Jan 22, 2026
Reserved
Jan 20, 2026

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Description

ACE vulnerability in configuration file processing by QOS.CH logback-core up to and including version 1.5.24 in Java applications, allows an attacker to instantiate classes already present on the class path by compromising an existing logback configuration file.

The instantiation of a potentially malicious Java class requires that said class is present on the user's class-path. In addition, the attacker must have write access to a configuration file. However, after successful instantiation, the instance is very likely to be discarded with no further ado.

Scores

CVSSScoreVectorSource
4.01.8 LowCVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/S:N/AU:N/RE:M/U:GreenNCSC.ch

Weaknesses

  • CWE-20 Improper Input Validation

Affected Products

ProductVersions
Logback-coreQOS.CH Sarl
  • 0.9.20 through 1.5.24Affected
  • 1.5.25Not affected

References

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